There is no doubt that everyone at some time in their life has had a vacation that went horribly wrong, something they may laugh about now but really didn't seem all that funny at the time that it happened. Things like flights being delayed or even canceled, the car broke down in the middle of nowhere, someone got hurt, etc. You can make an attempt to avoid such things if you are well prepared and do some good planning for your vacation.
No matter where you plan your holidays to it is always a very good idea that you do research on the place that you are going to vacation at. Make sure that this research includes things that are currently going on in and around the area, especially if it's another country. A good example would be if you were going to a different country and you weren't aware of the current affairs of the country and you arrived there right in the middle of a military takeover of the government. You also wouldn't want to go to another state right when a tornado or hurricane might be touching down. So make sure you know what's going on in the place you are planning to visit.
If you are taking your own vehicle it's really a good idea if you make sure your care has a tune up and is in good running condition before you even leave your driveway for the trip. Make sure every little thing your mechanic might find that could be an issue later on, is fixed before your vacation. This may cost you a little extra but it's better than being stranded in the middle of nowhere.
If you are flying to your destination, make sure you research the airline you are considering and see if there are any kind of problems that the airline might be having issues with. Make sure you have airline contact numbers and their customer service numbers so that if you do have any problems you can contact people that might be able to help you.
No matter how you travel make sure that you have some sort of first aid kit with you at all times during your vacation with your family. You should also know how to do first aid as well in case there is a time that arises that you can't seek medical help immediately. This is one thing that could save a life.
You should at all times have some sort of list with all the people that are important contacts should anything happen. If you have a cell phone make sure to put all of these numbers on your phone. These numbers should include a couple of neighbors, close relatives, someone you work with you are close to, your doctor and even a lawyer if you have one. These numbers are especially important if you are in a different country and disaster strikes.
It's always a good idea to have plenty of things for the kids and family to do to keep themselves occupied is something does happen to go wrong and you get stuck somewhere. Make sure to have plenty of games, crosswords, Sudoku, books, cards, music and even DVD's if you have a portable DVD player.
Final Note: Whatever you do, don't make yourself crazy over planning for possible disasters. These can and will happen but if you are obsessed by it you are going to take away all the fun you should be having with your family while you are on vacation.